Flashcards in Quiz 4 Deck (20)
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1
A method that is associated with an individual object is called ________.
A class instance.
2
An object is an instance of a ________.
class
3
Analyze the following code.
class Test {
public static void main(String[ ] args) {
String s;
System.out.println("s is " + s);
}
}
The program has a compilation error because s is not initialized, but it is referenced in the println statement.
4
Analyze the following code.
public class Test {
int x;
public Test(String t) {
System.out.println("Test");
}
public static void main(String[ ] args) {
Test test = new Test();
System.out.println(test.x);
}
}
The program has a compile error because Test does not have a default constructor.
5
Given the declaration Circle x = new Circle(), which of the following statement is most accurate?
x contains a reference to a Circle object.
6
Given the declaration Circle[ ] x = new Circle[10], which of the following statement is most accurate?
x contains a reference to an array and each element in the array can hold a reference to a Circle object.
7
Suppose s is a string with the value "java". What will be assigned to x if you execute the following code?
char x = s.charAt(4);
Nothing will be assigned to x, because the execution causes the runtime error StringIndexOutofBoundsException.
8
The keyword ________ is required to declare a class.
class
9
What is displayed by the following code?
public static void main(String[ ] args) throws Exception {
String[ ] tokens = "Welcome to Java".split("o");
for (int i = 0; i
Welc me t Java
10
What is the output of the following code?
String s = "University";
s.replace("i", "ABC");
System.out.println(s);
University
11
public class Test {
public static void main(String[ ] args) {
String s1 = "Welcome to Java!";
String s2 = "Welcome to Java!";
if (s1 == s2)
System.out.println("s1 and s2 reference to the same String object");
else
System.out.println("s1 and s2 reference to different String objects");
}
}
s1 and s2 reference to the same String object
12
What is the output of the following code?
public class Test {
public static void main(String[ ] args) {
String s1 = new String("Welcome to Java!");
String s2 = new String("Welcome to Java!");
if (s1 == s2)
System.out.println("s1 and s2 reference to the same String object");
else
System.out.println("s1 and s2 reference to different String objects");
}
}
s1 and s2 reference to different String objects
13
What is the output of the following code?
public class Test {
public static void main(String[ ] args) {
String s1 = new String("Welcome to Java!");
String s2 = new String("Welcome to Java!");
if (s1.equals(s2))
System.out.println("s1 and s2 have the same contents");
else
System.out.println("s1 and s2 have different contents");
}
}
s1 and s2 have the same contents
14
What is wrong in the following code?
class TempClass {
int i;
public void TempClass(int j) {
int i = j;
}
}
public class C {
public static void main(String[ ] args) {
TempClass temp = new TempClass(2);
}
}
The program has a compilation error because TempClass does not have a constructor with an int argument.
15
When invoking a method with an object argument, ________ is passed.
the reference of the object
16
Which of the following statements is most accurate? (Choose two.)
A reference variable refers to an object.
An object may contain the references of other objects.
17
Which of the following statements is preferred to create a string "Welcome to Java"?
String s = "Welcome to Java";
18
________ is a construct that defines objects of the same type.
A class
19
________ is invoked to create an object.
A constructor
20